Magnetic drive construction



July 4, 1950 G. E. FORD MAGNETIC DRIvE coNsTRucTloN Filed Feb. 24, 194'? is zo Patented July 4, 1950 MAGNETIC DRIVE CONSTRUCTION George E. Ford, Brighton, N.

Y., assignor to Qualitrol Corporation, East Rochester, N. Y., a corporation of New York Application February 24, 1947, Serial No. I730,646

l 6 Claims.

This invention relates to a magnetic drive. An object of the invention is the provision of a generally improved, less expensive, and more satisfactory magnetic drive, and the provision of an improved, less expensive, and more satisfactory method or process of manufacturing such a drive.

Magnetic drives are used in many different locations, for driving many different things. For many uses, the magnetic drives already known are quite satisfactory. However, particularly diilicult conditions of use are involved when the magnetic drive is immersed in a body of uid containing magnetic foreign matter, such as iron filings, steel chips, etc., and it is one of the objects of the present invention to provide a drive which is particularly satisfactory under those conditions of use.

Still another object is the provision of a drive which may be mounted to turn on a horizontal or approximately horizontal axis, which axis is located Ibelow the liquid level oi the tank or container in which the magnetic drive is located, and yet which will have a long trouble-free life notwithstanding the fact that there may be metallic chips in the liquid in which the drive is immersed.

A further object is the provision of an improved construction for mounting the moving parts of the magnetic drive and for limiting the extent of movement thereof, which construction gives a more rigid and satisfactory bearing to the moving parts and which also is relatively inexpensive to make.

A still further object is the provision of a magnetic drive construction so designed that one of the main mounting members, which in prior magnetic drives has heretofore required extensive machining, requires very little machining in the present improved construction.

A still further object is the provision of simplilied, improved, and less expensive methods of manufacturing a magnetic drive.

These and other desirable objects are accomplished by the construction disclosed as an illustrative embodiment of the invention in the following description and in the accompanying drawings forming a part hereof, in which:

Fig. 1 is a front elevation of a construction in accordance with a preferred embodiment of the invention;

Fig. 2 is a section taken substantially on the line 2--2 of Fig. l, on an enlarged scale;

Fig. 3 is a section taken substantially on the line 3-3 of Fig. 2; and

Fig. 4 is an exploded view of a fragment of the construction shown in Fig. 2, at an intermediate stage in the manufacturing operation.

The same reference numerals throughout the several views indicate the same parts.

There is indicated at II a wall of a tank or container. which may be a pressure container holding liquid under substantial pressure, but is not necessarily so, as the liquid in the container II may be at atmospheric pressure. Merely as an illustrative example, the container II may be an electric transformer casing, filled with insulating oil. 'I'he container is provided with an opening I3 surrounded by a thickened flange I5 to which is secured, as by bolts I1. the main mounting plate or closure plate I9 which extends entirely across the opening I 3 in an imperforate manner, thus completely closing and sealing the opening Il. If desired, a gasket 2| mounted in an annular grove on the rear face of the main plate I9 may press against the front of the flange I5 on the tank, thus aiding in sealing the joint betweenthe plate I9 and the tank.

Heretofore a main closure plate or mounting plate such as the plate I9 has been so designed as to require a number of machining operations, usually on both its front face and its rear face. According to the present invention, this main plate I9 is designed as a forging, and requires practically no machining operations. The few machining operations which are required consist merely of the formation of the annular grove for receiving the gasket 2I (if such a gasket is desired, it being frequently omitted) and the machining (if necessary) of the periphery or circumference of the plate in order tc ilt the bezel as mentioned hereafter, and the drilling and threading of the radial holes in which the bezel holding screws flt, as mentioned hereafter, and the drilling of the marginal holes through which the holding bolts or screws I1 extend.

In order to reduce, to a great extent, the machining which would otherwise be required, the

. mounting plate of the present invention has its central portion of its rear face originally forged in the shape shown in the left hand part of Fig. 4 of the drawings, including an annular bevelled shoulder 21 surrounded by an upstanding flange 29. A metallic tube 3| has its forward end flared as at 33 at an angle to flt the bevelled shoulder 21. The parts are brought together from the position shown in Fig. 4 so that the flare 33 fits against the angular shoulder 21, and then the upstanding flange 29 is staked down or bent over from the upstanding position shown in Fig. 4 to the position shown at 29a in Fig. 2, thus overlying 4the flared portion 33 of the tube 3| and arranca holding the tube securely and immovably to the rear face of the main mounting plate i9.

The rotatable shaft of the magnetic drive is indicated at 4| and is supported by passing with a snug rotary t through central holes in two cup shaped bearing members 4t and t5 which are pressed into and have a tight press fit in the tube 3l, at points therein which are spaced from each other and .also spaced from the front and rear ends of the tube. Near its forward end the shaft 4l carries a spacing member lil, in front of which is a pemanent magnet t9 usually and preferably of approximately U-shape, fixed on the shaft by e. staked or riveted portion Eat. In front of the magnet 49 the shaft has a reduced portion projecting forwardly as at 53 and terminating in a somewhat pointed end 65 having'a small at extremity bearing against the iiat central part ci the rear face of the member it.

The magnetic drive shaft lil may be driven in various ways, depending upon what condition is to control the magnetic drive. If the drive is to be responsive, for example, to liquid level, there may be provided a oat tl mounted on a float arm 63 extending approximately radially with respect to the shaft di, through a diametrical hole in a hub or cap member d5 having an axial bore, which receives and is mounted on the rear end of the shaft 4l. A pin @l pins the cap t5 to the shaft v4I and the outer end of the pin is sunk below the outer face of the cap 55, and the cap @5 is peened over the outer end of the pin el to hold it in place. The oat rod t3 is held in place in its bore by means of a set screw te threaded into a radial opening in the cap @5.

It will be noted that the oat arm swings approximately in a plane perpendicular to the axis of the shaft il and located between the rear end of the tube 3l and the rear bearing cup d5. The rear end of the tube 3l, rearwardly of the cup 15, may be notched out or cut out along one side so as to leave a top edge 'El and bottom edge l which form stops or abutments for limiting the upward and downward swinging of the oat arm t3, and this same notch extends axially along the tube 3l approximately to the rearmost bearing member 45, thus allowing ample space for access to the cap 65 when initially assembling the cap on the rear end of the shaft di and when assembling the oat rod 63 in the cap and tightening the set screw 69, which operations are performed through the large notch with little trouble.

With this arrangement, a particularly satisfactory construction results. Machining work is reduced to a minimum. The assembly is easy and can be done inexpensively. The support of the shaft 4! is particularly rigid and effective, and the shaft is protected from lateral blows or damage by the sturdy tube 3l which, in turn, is mounted in an extremely sturdy yet easy manner on the rear face of the main plate i9. Forwardly of the rear cup bearing t5, the tube 3l has no lateral openings whatever, hence chips cannot readily get to the magnet 48. As the insulating oil or other liquid within the tank Il circulates around the parts of the magnetic drive, any chips or other magnetic foreign matter carried thereby and coming within the magnetic influence of the magnet 49 will be stopped by the outside of the tube 3l and will simply cling to the outer surface of the tube, where they are far away from all moving parts and will do no damage. ny chips which happen to get inside the rear end of the tube 3|, rearwardly of the cup bearing 45, are so far away from the magnet 4S that they are not subject to any substantial magnetic influence and so are not likely to be drawn toward the bearing joint between the shaft il and the cup d. The magnetic influence being so slight at this rear bearing of the shaft fil, any chips located at that point are likely to be easily washed away by the continued circulation of the oil or other liquid within the tank l l. The large notch whose upper and lower edges are shown in ll and. ld, respectively, promotes free circulation of the oil or other liquid within the rear end of the tube 3i so as to allow sufficient circulation to wash away any chips that may be carried to this part of the apparatus.

The magnetic drive consists of two separate units, a driving unit and a driven unit. The driving unit comprises the parts' already described, and the novelty of this present invention resides mainly in this driving unit. The driven unit, detachably mounted on the front of the main plate it, may be of any suitable form, subject to the inuence of the driving magnet fie. For example, in the form here shown, there is a bezel 8i having a rearwardly extending annular ange fitting snugly over the periphery of the main mounting plate i9 as seen in Fig. 2, and held thereto by screws 35 extending radially into tapped openings in the edges of the main plate it. This bezel carries a case S3 having a stepped marginal edge, the outer step of which has a tight press fit in the bezel, and a U-shaped gasket et pressed tightly lbetween the bezel and the front step of the case d3 embraces the edge of a closure glass 8l extending across the front of the case.

At the center of the case 83, in axial alignment with the shaft l l, is a stationary pivot @l mounted by being riveted to the case. Rotatable on this pivot 8l is a sleeve et to which is xed a pointer di and a permanent magnet 93, preferably of U-shaped form as seen, which constitutes the driven magnet and is under the magnetic influence of the driving magnet de, s'o that whenever the magnet iii turns on its rotary axis, themag= net S3 will follow. The pointer 9H sweeps across suitable index markings or graduations 95 on a dial plate @l secured to the case t3 by rivets 99.

The improved construction herein disclosed is particularly effective in eliminating trouble here tofore caused by the driving unit being immersed in oil or other liquid containing magnetic foreign matter such as chips or lings, which have here-- tofore been carried around by the circulation of the oil or other liquid in the tank in such many ner as to come into contact with the magnet of` 55 the magnetic drive and gradually build up an accumulation of foreign matter on the magnet to such an extent that frequently the accumulation of foreign matter has contacted with other parts and thus prevented proper functioning of the' 00 magnetic drive, and in many instances the foreign matter has gotten in the bearings of the magnetic drive shaft. These difficulties are avoided by the present construction, and the magnetic drive herein disclosed can be used elciently in a submerged position, as distinguished from many of the prior magnetic drives which are not suitable for use in a, submerged position and which can be used effectively only when the magnet is located above .the level of the liquid so as to be 7o away from any magnetic foreign matter carried by the liquid.

It will be understood, of course, that the main` plate i9, and preferably also the tube 3 l, shaft 4l, cups d3 and 45, and in fact allof the metallic parts other than the permanent magnets t9 and atrasos I3, are made of some non-magnetic metal or alloy, auch as copper, brass, aluminum, etc.

In assembling the driving unit, the cups are preferably first pressed into their proper locations in the tube, then the shaft with the magnet already fixed thereon is inserted in the bearing holes'of the cups, and then the flared end of the tube is assembled to the main plate and the flange on the plate is swaged or staked down onto the flare of the tube. 'I'he cap may be pinned to the rear end of the shaft either before or after the tube is fastened to the plate.

Certain subject matter disclosed but not claimed herein is claimed in the co-pending application of George E. Ford, Serial No. 632,683, iiled December 4, 1945, now Patent No. 2,473,581, patented June 21, 1949, for indicating instruments.

It is seen from the foregoing disclosure that the above-mentioned objects of the invention are admirably fulfilled. It is to be understood that the foregoing disclosure is given by way of illustrative example only, rather than by way of limitation, and that without departing from the invention,

the detalls may be varied within the scope of the appended claims.

In addition to the advantage of eliminating certain machining operations which have heretofore been required, the present construction has the further advantage that, by eliminating machining operations; the danger of uncovering porosity in the forging inated. Hence, the main plate I9, Whether it 'be a forging (as preferred) or a casting, has a hard, dense rear surface, so that an exceptionally tight and leak-proof construction is obtained.

What is claimed is:

l. A magnetic drive unit comprisingv a plate adapted to form a closure for an opening in a tank, said plate having an imperforate portion adapted to be mounted in position to extend across the tank opening, an inclined annular seat on the rear face of said plate, a tube extending rearwardly from the rear face of said plate and having a forward end flared to seat on said inclined portion of said plate, a plurality of partitions extending across said tube at spaced intervals therein and forming bearings, a shaft extending longitudinally in said tube and having bearings in said partitions, and a magnet fixed to said shaft near the forward end thereof closely adiacent the rear face of said plate, one of said partitions being spaced substantially rearwardly from said magnet, land the portion of said tube between said one of said partitions and said plate being imperforate so that chips of magnetic material surrounding said tube cannot come into contact with said magnet. 1,

2. A magnetic drive unit comprising a plate adapted to extend across and form a closure for an opening in a liquid container or the like, a tube mounted on the rear face of said plate and extending rearwardly therefrom so as to extend through the opening into the liquid within the container when the plate is mounted across said opening, the rear end of said tube having a notch extending throughout only a portion of the circumference of the tube, a plurality of bearing members extending across the interior of said tube at spaced points therein, a shaft rotatably mounted in said bearing members, a magnet carried by said shaft and arranged in close proximity to the rear face of said plate, and a float arm operatively connected to said shaft near the rear end thereof and arranged in cooperative reor casting is also elimlation to said notch so that the edges of said notch forms stops limiting the swinging movement of said float arm in both directions.

3. A magnetic drive unit including a mounting plate adapted to extend across and form a closure for a lateral opening in a liquid tank below the maximum liquid level therein, a tube extending rearwardly from the rear face of said plate and supported thereby, a plurality of cup shaped members each having a tight pressed llt inside said tube and arranged at spaced intervals therein, each of said cup shaped members having a hole therethrough, a shaft mounted for rotation in and extending snugly through and having bearings in said holes of said cup shaped members, at least one of said cup-shaped members being substantially imperforate except where said shaft passes through it and serving as a sealing partition to prevent foreign matter from passing axially along said tube past such partition, a magnet mounted on said shaft between said plate and that one of said cup shaped members which is closest to said plate, a float arm operatively connected to an end of said shaft remote from said plate, said float arm extending substantially radially with respect to said shaft, and abutment edges on said tube forming limit stops for engaging said float arm to limit the swinging thereof and thereby to limit the rotation of said shaft.

4. A magnetic drive unit comprising a plate having near the center of its rear face an annular seat, a tube having a front end flared outwardly and mounted against said seat of said plate, an integral flange on said plate overlying the flared end of said tube to hold said tube in place, a plurality of cup shaped members fitted within said tube at points spaced from each other and spaced from the front and rear ends of said tube, said cup shaped members having axial openings therethrough, a shaft extending through said axial openings and mounted for rotation therein, a magnet mounted on said shaft near the forward end thereof, between said plate and said cup shaped member closest to said plate, said magnet being in close proximity to the rear face of said plate and the portion of said tube between said cup shaped member and said plate being imperforate so that foreign matter may not enter laterally through said tube to said magnet, a float arm operatively connected to said shaft adjacent the rear end thereof, and marginal apertures extending through said plate in directions approximately parallel to said tube and at a substantial distance radially outwardly from said tube so that fastening means may extend through said apertures to fasten said plate to a liquid container or the like.

5. A magnetic drive unit comprising a plate having near the center of its rear face an annular seat, a tube having a front end flared outwardly and mounted against said seat on said plate, an integral flange on said plate overlying the flared end of said tube to hold said tube in place, a plurality of cup shaped members fitted within said tube at points spaced from each other and spaced from the front and rear ends of said tube, said cup shaped members having axial openings therethrough, a shaft extending through said axial openings and mounted for rotation therein, a magnet mounted on said shaft near the forward end thereof, between said plate and said cup shaped member closest to said plate, said magnet being in close proximity to the rear face of said plate and the portion of said tube between said cup shaped member and said plate 7 being imperforate so that foreign matter may not enter laterally through said tube to said magnet, a. hub mounted on the rear end of said shaft, a pin connecting said hub non-rotatably to said shaft, said hub being peened over said pin, a substantially radial opening in said hub, a dost arm mounted in said radial opening in said hub.

said oat arm extending approximately radially with respect to said shaft, and a oat carried by said float arm.

6. A construction as described in claim 5, in which said oat arm is mounted to swing spproximately in a plane transverse to the axis di said shaft and located between the rear end of said tube and that vone of said cup shaped members which is closest to the rear end of said tube, and in which a side wall of said tube between the rear end and said one of said cup shaped meinbers is cut away to allow space for swinging movement of said oat arm, the edges of said tube adjacent the cut away portion serving es stese to limit the extent of swinging movement of the.

The following references are oi reeerd im the ille ci this petent:

mm STATES PA l Number Name Date 591.395 1 Fay Get. i2, ist? Liltd Sheldon Dec. i, iiii i Knight Oct. 13 lilt 1,6%,838 Fendi ee. d, lsl M2673 Lewis Mai'. 2i), i938 22313158 Davis Feb. ll, istil. 2,241,983 Connolly Mey 13, @di 2,356,652

Connolly et al Aug. 22, lte 

